If you do not have a menu bar on the left Click Here
You may return to this page by selecting --Gemology:Value-- from the menu.

How gemstones are valued

Two major factors influence the price of gems. The property of the particular gem in question, or the infamous 4-C's, and the characteristics of the gemstone type, such as the rarity of the gem, difficulty of producing the gem, and the popular opinion of the value of the gem. Rarity and perfection of a stone are usually perceived to control a stone's cost, but these two factors alone only begin to set the price.
Tsavorite Garnet courtesy of theimage.com
Gemstone prices in general are a result of the rarity, availability and perceived value of a stone. Rarity is generally a simple matter of how many stones exist in the world, from the discovered, but un-mined, to the finished stone in a jewelry setting. Availability of the stone is a product of not only rarity, but political social and economic factors as well. Wars, labor disputes, taxation, export/import restrictions, monopolization of raw goods etc. all work to make an otherwise common stone unavailable and therefore more costly. Perceived value is not a large factor in most colored stones, but this, combined with the monopolization of diamond rough by DeBeers, is responsible for 90% of the cost of diamonds. Based on rarity alone, a one carat diamond of the quality normally used in engagement rings should retail for under $50 per stone.
Topaz courtesy of theimage.com
The price for a single stone of any given type is based on the 4 C's of the Jewelry industry: Color, Cut, Clarity, and Carat weight. Each of these factors must be evaluated both individually and collectively in determining the price. Any one of these characteristics may become the primary factor in determining the stone's price, if that characteristic is reaching an extreme value. Color or clarity will often be the extreme factor in the price for many stones. Diamonds best demonstrate the wide range in prices for these two factors.
Tourmaline courtesy of theimage.com
The following chart is an example of prices at one retailer for various quality 1 carat round stones:
Color Flawless Very Very
Slightly Included
Very
Slightly Included
Slightly
Included
Included
D 15,000 9,000 7,100 5,400 3,600
F 9,000 7,200 6,500 4,800 3,200
H 6,250 5,750 5,200 4,300 3,000
J 4,500 4,200 3,900 3,400 2,500
L 3,600 3,400 3,200 2,700 2,000
(Non round shapes are priced at about 66% of the same weighted round stone)

Color and Clarity ratings are based on the gem type. Color in diamonds is ranked as 'D' through 'W', with "D" being the best and "W" being the worst. Diamond clarity is also well defined and ranked as "Flawless" down to "Included". Diamonds are usually sold with the color and clarity specified. Most other stones are given a numerical value for color, and although the Included to Flawless scale is used, the meanings may vary depending on the stone type. Although emeralds, rubies, and sapphires may be graded this way at times, most other stones are not graded by the same standards except the most valuable specimens. Most stones, other than diamond, are usually sold with a subjective grade by the seller with a grading scale of "AAA", "AA", and "A" or a scale of "A", "B", and "C".

Carat weight is important not only to use as a multiplier for weight x price per carat = price per stone calculations, but the larger a stone, the more rare it will be, therefore the higher per carat price.
The prices for a VVS diamond with a "D" color from the same retailer as in the first chart range from $3,000 per carat for a ¼ carat stone, to $35,000 per carat for a 5-carat stone. The price per stone, based on these prices, will range from $750 to $175,000.
Size in Carats .25 .5 1 2 3 4 5
Price Per Carat $3,000 $5,500 $9,000 $18,500 $24,200 $27,000 $35,000
Price Per Stone $750 $2,750 $9,000 $37,000 $72,600 $108,000 $175,000

The gemstone is cut to bring out the beauty of the gem. This is achieved by a very precise cut based on angles and facet sizes determined to provide the greatest amount of reflected light possible. The size of the table, or the flat, top surface of the stone, the depth of the stone, from top to bottom, and the ratio of the amount of the stone above and below the girdle, or widest part of the stone, are of primary importance. If the table is too small, not enough light enters the stone. If the depth is too great or shallow, or the depth ratio is wrong, the light that enters through the table will be reflected out the sides or bottom of the stone.

Home     Site Map


Copyright © 2005 by Gem And Mineral Info.com.
All descriptions and images, except where noted, are the property of Gem And Mineral Info.com
Where noted images and descriptions are used with permission of copyright holder as indicated.